docs: def segment(f, output, target_duration, mpegts):
      """Segment command."""
      try:
          target_duration = int(target_duration)
      except ValueError:
          exit('Error: Invalid target duration.')
  
      try:
          mpegts = int(mpegts)
      except ValueError:
          exit('Error: Invalid MPEGTS value.')
  
      WebVTTSegmenter().segment(f, output, target_duration, mpegts)